.navbar-dark {
    height: 60px;
}
.main-container {
    display: flex;
}
.menu {
    width: 200px;
    height: calc(100vh - 60px);
    background: #343a40;
}
.nav-header {
    display: block;
    text-align: center;
    line-height: 35px;
}
.secondmenu {
    display: block;
    text-align: center;
    line-height: 35px;
}
/*控制菜单箭头*/
.nav-header.collapsed > span.glyphicon-chevron-toggle:before {
    content: "\e114";
}
.nav-header > span.glyphicon-chevron-toggle:before {
    content: "\e113";
}
.secondmenu a {
    font-size: 12px;
    color: #4A515B;
    text-align: center;
}
.secondmenu li.active {
    background-color: #eee;
    border-color: #428bca;
}